#include "config.h"

#include <avr/io.h>
#include <util/delay.h>
#include <stdbool.h>

#define LCD_DATA_PORT   PORTB
#define LCD_DATA_DDR    DDRB
#define LCD_RS_PIN      PB1
#define LCD_EN_PIN      PB2
#define LCD_DB4			PB3
#define LCD_DB5			PB4
#define LCD_DB6			PB5
#define LCD_DB7			PB6

// Delay constants from the datasheet. These are mostly in nanoseconds
#define LAG 10
#define TW 300
#define TSU1 100

void lcd_4bit_init() {
	LCD_DATA_DDR = 0xFF;
	LCD_DATA_PORT = (1 << LCD_DB5);
	LCD_DATA_PORT &= ~(1 << LCD_RS_PIN);
	_delay_us(1);
	LCD_DATA_PORT |= (1 << LCD_EN_PIN);
	_delay_us(1);
	LCD_DATA_PORT &= ~(1 << LCD_EN_PIN);
	_delay_us(1);
	LCD_DATA_PORT &= ~(1 << LCD_DB5);
	_delay_us(1);
}

void lcd_send(bool rs, uint8_t data) {
	LCD_DATA_DDR = 0xFF;
	LCD_DATA_PORT = 0x00;

	LCD_DATA_PORT |= (data >> 4) << 3;
	_delay_us(1);
	
	// If rs (actual text data), set RS pin high
	if(rs == true) LCD_DATA_PORT |= (1 << LCD_RS_PIN);

	// Pulse enable
	_delay_ms(2);
	LCD_DATA_PORT |= (1 << LCD_EN_PIN);

	_delay_us(1);
	LCD_DATA_PORT &= ~(1 << LCD_EN_PIN);

	//_delay_us(1);
	
	// Clear data pins
	LCD_DATA_PORT &= ~(0x0F << 3);
	
	// Mask the lower bits and shift accordingly
	LCD_DATA_PORT |= (data & 0x0F) << 3;
	_delay_us(1);
	
	// Pulse enable
	LCD_DATA_PORT |= (1 << LCD_EN_PIN);
	_delay_us(1);
	LCD_DATA_PORT &= ~(1 << LCD_EN_PIN);
	_delay_us(1);
	LCD_DATA_PORT &= ~(0x0F << 3);
	
	LCD_DATA_PORT &= ~(1 << LCD_RS_PIN); // RS Low
}

void lcd_init() {
	_delay_ms(100);
	lcd_4bit_init();

	//lcd_send(1, 0b01111000);
	lcd_send(0, 0x01); // Clear screen
	lcd_send(0, 0x02); // Return home
	lcd_send(0, 0b00001100); // Display on, no cursor
	lcd_send(0, 0b00101000);
}

void lcd_clear() {
	lcd_send(0, 0x01);
}

void test_leds() {
		DDRB |= 0xFF;
		PORTB = (1 << LCD_DB4);
		_delay_us(1);
		PORTB = (1 << LCD_DB5);
		_delay_us(1);
		PORTB = (1 << LCD_DB6);
		_delay_us(1);
		PORTB = (1 << LCD_DB7);
		_delay_us(1);
		
		PORTB = (1 << LCD_EN_PIN);
		_delay_us(1);
		PORTB = (1 << LCD_RS_PIN);
		_delay_us(1);
		PORTB = 0x00;
}

void lcd_set_cursor(uint8_t row, uint8_t col) {
	uint8_t position = 0x80;
	
	if (row == 1) position += 0x40;
	
	position += col;
	lcd_send(0, position);
}

// Takes a string and splits it over two lines if needed. Max length is 32 characters.
void lcd_write_string(const char* string) {
	uint8_t i = 0;
	while(string[i]) {
		if(i == 16) {
			lcd_set_cursor(1, 0);
			while(string[i] == ' ') i++; // Skip leading spaces on the new line
		}
		lcd_send(1, string[i]);
		i++;
	}
}

// Takes two separate strings and prints them on their corresponding row
void lcd_write_strings(const char* top, const char* bottom) {
	uint8_t i = 0;
	
	while (top[i]) {
		lcd_send(1, top[i]);
		i++;
	}
	
	i = 0;
	lcd_set_cursor(1, 0);
	while(bottom[i]) {
		lcd_send(1, bottom[i]);
		i++;
	}
	
}